1. Field of the Invention
This invention relates to a membrane system, which makes possible intercommunication via an enclosed passage way between successive, consecutive railway or road vehicles used to transport passengers and/or accompanied vehicles. The present invention employs an elastically deformable, self-supporting membrane in the form of concertina bellows to completely surround and enclose the exposed passage way preferably with a weathertight seal which also is substantially soundproof and fireproof.
2. Background Information
The term "concertina vestibule" characterizes the first generation of essentially weathertight means obtained by using multiple accordion like folds with flat walls made of a flexible material to connect the successive railway vehicles used for passenger transportation. Originally made of leather, these concertina vestibules are being constructed of waterproof rubber fabric as disclosed, for example, in French Patent No. 695.534 (SEBILLE). Such constructions need several round-off parts and superimposed layers of elastomer compounds.
A current method or technique of using concertina bellows, in particular on articulated auto-buses and tramways on rails, is to cut and crimp the waterproof fabrics of the membranes comprising the bellows. Sometimes, the waterproof fabrics may consist of superimposed materials layered in a complex structure so as to improve the insulation ability of the structure. These waterproof fabrics can alternatively be crimped on their exterior and interior periphery.
Various improvements to this technology are disclosed in patents European Patent No. 114.913 and French Patent No. 2.348.829, and French Utility Certificate No. 2.333.657 (HUBNER).
French Patent No. 2.328.141 (TAURUS) discloses improvements in the shape of pleats or accordion-like folds which comprise the form of the concertina bellows to make the bellows more self-supporting.
This type of concertina bellows are commonly manufactured in the form of flat parts then corrugated or shaped in pleated form, that is, an `accordion-like` shape. The concertina bellows must be further extended from a rest position, to the service position. The desired or required extended position would then be held by a tensile force exerted on the flanges when each end of the bellows is originally fastened to connect two consecutive vehicles, for example, railway or auto-buses.
Since the fabric or materials comprising the bellows have a relatively thin structure in the prior art, very little thermal and acoustical insulation was obtained.
French Patent No. 2.529.836 (TAURUS) represents a border between two possible types of vestibule membranes, in that the membrane represents a concertina bellows having thin walls, but the membrane is made by a molding process using polyurethane foam. The major disadvantage of such a design for a membrane resides essentially in the brittleness of the curved portions of the pre-formed corrugated membrane, which curved portions are thinner and lack reinforcement. The curved portions of the corrugations are usually the most vulnerable areas since these areas are almost completely exposed when fully extended such as, to be acted upon by any unfavorable climatic conditions, for example, rain, snow or intense sunlight.
The method for the construction of such a concertina vestibule is related to the more recently designed membranes used in railway applications in particular. The deformable membranes are usually manufactured on a molding mandrel and result in a sort of closed ring, tunnel-like structure around the passage way between railway vehicles. Such membranes, which do provide a covered passage way between the railway cars and have some thermal and acoustical insulation properties, are referenced, but without a description of the membrane itself, in French Patent No. 2.496.030, French Patent No. 2.573.714 (FAIVELEY), and French Patent No. 2.568.195 (SIG). Additionally, each of these three patents does describe a device which allows for the movement of passengers between vehicles. The design of such membranes is intended to avoid the placement of facing end doors, the acoustical insulation beimg supplied by sheathing the membrane by sliding partitions and not being supplied by the membrane itself. The three patents describe in detail the floors and rigid assembly means, but not the membrane itself.
The prior art appears to recognize many of the requirements for such membranes. However, the prior art does not include any technique which is capable of correctly satisfying the contradictory requirements of having a flexible but self-supporting membrane, which also provides thermal and acoustical insulation, protection against the wind caused by the speed of travel and at the same time is economical to produce and of light weight.
FAIVELEY and CAOUTCHOUC MANUFACTURE ET PLASTIQUES have jointly filed Patent Application EP 0336809, which discloses an elastically deformable membrane capable of meeting the new requirements expressed by the railway industry. This membrane is also a one-piece construction which has a corrugated surface formed by parallel rings and has a sinusoidal cross section while in the relaxed state. The one-piece membrane connects with two fastening flanges to the ends of successive railway cars and is partly compressed when installed. The thickness of the wall of the membrane is essentially constant in the straight portions as well as in the curved, non-developable portions.
However, further experimentation, with membranes of a constant thickness and constructed according to the above design to cover very large passage ways, has shown that these membranes are too flexible. These membranes, with textile reinforcements in the straight portions and unreinforced elastomer layers, have good mechanical qualities in the core, and also have soundproof and fireproof qualities in the coatings. But these membranes are so extremely flexible that their horizontal portions have an exaggerated curve and lack the self-supporting capabilities necessary to cover the very large and very high intercommunication passage ways, such as on the two story trains used to transport cars and trucks, and commonly called auto-trains.